Every time an user tries to delete an attachments this warning pop ups making impossible to delete such file.

Odoo Server Error

Traceback (most recent call last):
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 546, in _handle_exception    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 583, in dispatch    result = self._call_function(**self.params)
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 319, in _call_function    return checked_call(self.db, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/service/model.py", line 118, in wrapper    return f(dbname, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 316, in checked_call    return self.endpoint(*a, **kw)
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 812, in __call__    return self.method(*args, **kw)
  File "/home/openerp/instancias/estable/8.0/server/openerp/http.py", line 412, in response_wrap    response = f(*args, **kw)
  File "/home/openerp/instancias/estable/8.0/server/addons/web/controllers/main.py", line 944, in call_kw    return self._call_kw(model, method, args, kwargs)
  File "/home/openerp/instancias/estable/8.0/server/addons/web/controllers/main.py", line 936, in _call_kw    return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 268, in wrapper    return old_api(self, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 399, in old_api    result = method(recs, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/l10n_mx/l10n_mx_payment_cfdi/models/ir_attachment_payment.py", line 792, in unlink    ('file_xml_sign', 'in', self.ids), ('file_pdf', 'in', self.ids)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 266, in wrapper    return new_api(self, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 508, in new_api    result = method(self._model, cr, uid, *args, **old_kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/models.py", line 1650, in search    return self._search(cr, user, args, offset=offset, limit=limit, order=order, context=context, count=count)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 268, in wrapper    return old_api(self, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/models.py", line 4687, in _search    query = self._where_calc(cr, user, args, context=context)
  File "/home/openerp/instancias/estable/8.0/server/openerp/api.py", line 268, in wrapper    return old_api(self, *args, **kwargs)
  File "/home/openerp/instancias/estable/8.0/server/openerp/models.py", line 4498, in _where_calc    e = expression.expression(cr, user, domain, self, context)
  File "/home/openerp/instancias/estable/8.0/server/openerp/osv/expression.py", line 662, in __init__    self.parse(cr, uid, context=context)
  File "/home/openerp/instancias/estable/8.0/server/openerp/osv/expression.py", line 830, in parse    raise ValueError("Invalid field %r in leaf %r" % (left, str(leaf)))
ValueError: Invalid field 'file_input' in leaf "<osv.ExtendedLeaf: ('file_input', 'in', [149387]) on ir_attachment_payment (ctx: )>"